tanbul 2004 
EVALUATION OF GEOMETRICAL ACCURACY IN DISPLACEMENT MONITORING 
OF ENGINEERING STRUCTURES USING CLOSE-RANGE PHOTOGRAMMETRY 
a A. Mokarrami ,” H. Ebadi 
* Mahab Ghodss Consulting Engineers,#95,Peyvandi Alley,Kargozar St., Zafar Ave.,Tehran,Iran 
Email: aylin_mokarrami@yahoo.com 
® K.N.Toosi University of technology, Faculty of Geodesy and Geomatics Eng., Valiasr Ave., Tehran,lran, 
Email: ebadi@kntu.ac.ir 
Session: PS ICWG V/III 
KEY WORDS: Close range , Monitoring , Non-metric ,Digital , Photography , Adjustment ,Calibration , Accuracy 
ABSTRACT: 
Almost every part of the earth's surface and even man-made structures are subject to variations of size, shape and position with time. 
The period of these changes differs from case to case depending on the individual characteristics of the deformable body. 
The determination and sometimes interpretation of these movements is the objective of deformation surveys. Photogrammetric 
methods are suitable for monitoring displacements, because a photograph represents a remote, complete and instantaneous record of 
an object. An instantaneous record of particular situation which may be changing in time, together with a complete coverage, is most 
appropriate for a phenomenon such as a moving object. 
Here, rotary kiln in Abyek cement factory has been chosen for study. The main purpose of monitoring these kilns is to determine the 
displacement of the centre of the kiln in the place of rollers. On the other hand, we want to monitor the displacement of the kiln in 
order to avoid dangers due to horizontal and vertical movements. Close-Range photogrammetric technique was chosen to carry out 
this research. 
The results according to the ground coordinate of the check points, accuracy derived from variance-covariance matrix and computing 
the displacements for four points instead of one point, are acceptable and mm accuracy for determining the coordinates shows that 
this method is suitable for monitoring studies, especially for specific cases like this case which popular geodetic methods are not 
applicable due to high temperature of the kiln area. 
1. INTRODUCTION 
Almost every part of the earth's surface and even man-made 
Structures are subject to variations of size, shape and position 
with time. The period of these changes differs from case to case 
depending on the individual characteristics of the deformable 
body. The determination and sometimes also the interpretation p'=p+Ap 
of these movements is the objective of deformation surveys. 
Usually, for monitoring purposes the entire deformable body is X 
represented by a number of properly distributed discrete points Figure 1. Position vectors p and p' and displacement vector Ap 
called detail points. Under certain circumstances, forces applied 
either by the surrounding matter or by direct contact or by A genera] displacement is expressed as the difference of the 
gravity cause the body to alter position and shape. The ^— coordinates between the two positions of point P. Thus, 
determination of these changes can be carried out by : 
monitoring the position of the detail points with respect to a ; 
reference system at time intervals depending on the frequency ApFSOPC-OPSQU-A vy z'-2)'=(0x ày àz) (2) 
and rate of motion. 
  
3. METHODS OF DISPLACEMENTS 
2. EXPRESSIONS OF DISPLACEMENTS MONITORING 
The aim of the monitoring campaign is to determine the 
magnitude and the direction of motion of the detail points 
representing the object. There are three major factors upon 
which the selection of a measuring method highly depends: 
e magnitude of displacements 
e frequency (rate) of movements 
€ accuracy requirements 
The position of a detail point P with respect to a Cartesian 
coordinate system may be defined in terms of magnitude 
(length) and direction of the radius vector p , That is, the 
position vector OP = p (Figure 1) and it is determined as : 
p=xi+yj+zk (1)